Process of utilizing lime-mud in the manufacture of fertilizers.



Y Fertilizers, of which the following is a speci- HUGH AFGALT, orBARZBEBTON, OHIO, assrenon 'ro COLUMBIA cnmncnr. COMPANY, or nannnnron,OHIO, A CORPORATION or PENNSYLVANIA.

No Drawing.

Specification of Letters Patent.

Tattented Feb. 13, 1912.

Application filed September 19, 1910. Serial No. 582,659.

To all whom it may concern:

Be it known that I, HUGH A. GAnT, a c1ti-- zen of the United States, andresiding at Barberton, in the county of Summit and State of Ohio, haveinvented certain'new and useful Improvements in Processes of UtilizingLime-Mud in the Manufacture of fication.

The invention relates to a process for treating phosphate rock with alime mud or by-product, to the end that the phosphoric acid in the rockmay be rendered soluble and available as a fertilizer, and the alkaliby-product, which would otherwise be waste.

material, may be utilized advantageously.

The process, while applicable to all phos phate rocks, has been foundparticularly advantageous as applied to low grade phosphate rocks, towhich the acid treatments commonly used are not profitably applicable.

In the manufacture of caustic soda on a commercial scale, soda ash orsodium carbonate is treated with lime with the following reaction,

' Na UU Get) H 0 CaCO 2NaOH sodium lime water calcium caustic carbonatecarbonate soda The caustic soda remains in solution'and the precipitatedcalcium carbonate is separated by filtration. The calcium carbonate iswashed with water to remove the caustic soda, but it is practicallyimpossible to free all of the caustic 'soda from this calcium carbonateand the two substances constitute substantially awaste product known aslime mud. J

In order to utilize the caustic soda in the alkali waste or lime mudwhich would thus otherwise be lost as well as the calcium carbonate, Imix the lime mud with phosphate rock and heat the mass in a furnace. Thecalcium carbonate is decomposed by the heat into carbonic acid andcaustic lime, which latter preventsrthe mass from fluxing and leavesthesoda free to unite with the phosphate elements of the rocks to form asoluble phosphate, the reactions depending upon the character of thephosphate rock and the process being applicable, I have found, to a widevariety of rocks. For example, when a mixture of lime. mud is mixed inthe proper proportions with pulverized phosphate rock and the massheated to a temperature of approximately 2000 Fahn, the soda present 1nthe lime mud combines with the phosphoric acidpresent in the phosphaterock forming a soluble sodium phosphate. In the case of the formation ofnormal sodium pyrophosphate the chemical reaction would be as follows:

4'NaOH+CaCO -I-Ca,(PO

N nai CaO-I-2I-LO-l-CO or in the case of tri sodium phosphate r 6NaOH+CaCQ 3 4) 2 Low grade phosphate rock- 1256 lbs.

Lime mud 1570 Soda ash 410 Water 314:

When mixed as above,'and thoroughly furnaced, about 2000 lbs. offinished fertilizer are secured, containing about 18% of 'solublephosphate. Where the lime mud is not washed thoroughly, and thepercentage of caustic soda remaining therein is large, the amount ofsoda ash or its equivalent may be reduced, 'or such compound entirelyeliminated depending on the quantity of caustic soda remaining in thelime mud.

The percentage of soluble phosphoric acid is proportionately higher whenhigher phosphate rocks are used. The percentage of lime mud can also bevaried so as to getthe best results in the furnacing operation and stillmaintain a high percentage of soluble phosphoric acid in thefurnacedmass.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent is the following 1 Theprocess of utilizing lime mud comprising calcium carbonate and causticment of sodium carbonate with lime and the separation of the-body of thecaustic soda from the calcium carbonate, which comprises mixing the saidlime mud with phosphate rock and fu'rnacin the mass.

L 3. The. process of utilizing the caustic soda remaining in the limemud produced in the manufacture of caustic soda and. consistingofvcalcium carbonate and caustic soda, which comprises mixing the saidlime mud with phosphate rock, and a sodium compound, and furnacing themass.

.4. The process of utilizin the caustic soda remaining in' the lime mudproduced in the manufacture of caustic soda and con- ]sisting of calciumcarbonate and caustic soda, which comprises mixin the said lime mud withphosphate rock, an soda ash, and furnacing the mass.

5. The process of utilizing lime mud comprising calcium carbonate havinga rela-- tively small amount of caustic soda mixed therewith, whichcomprisesmixingthe said lime mud with phosphate rock, and a sodiumcompound and furnacing the mass.

6. The process of utilizing lime mud comprising calcium carbonate havinga relatively small amount of caustic soda mixed therewith, whichcomprises mixing the said water and furnacing the mass.

7. The herein described process of utilizlizers, sai process comprisingthe mixing of said lime-mud with phosphate rock, the

tained in said lime-mud by the action of whi ch is produced under saidheat action the soda free to unite with the phosphate elements 01 therocks in the formation of a soluble phosphate. I H

In testimony whereof I have hereunto ed my name in the presence of thetwo scribed witnesses. v

' HUGH A. GALT.

Witnesses:

"R. H. CoPELANn,

heat in a furnace whereby the caustic lime prevents the mass fromfluxing and leaves.

lime mud with phosphate rock, soda ash and ing lime-mud in themanufacture of ferti--- I decomposition of the calcium carbonate con-

